Alrighty, so I solved the problem associated with Windows XP deployment of a Phonon application: I've just included every DLL for everything in Qt, and I'll slowly strip out, debug and strip out the waste. Now, the program no longer crashes, which is great, but, it doesn't show video!

It plays sound, moves the progress slider along, but doesn't render any video. The application runs fine, aside from the fact it has no visuals. So, any suggestions?

There is one or i guess two examples in Qt, one should be in example folder and other should be in demos ( I am not sure though) can you try running both of those with the same media file you are playing and see if those shows the video? this will give an insight is all your code okay?

I remember one thing now I had some problem related with phonon back in 2009 (not sure it was video not showing or what) and the reason was proper codec was not installed, so I will also suggest if you can download real player or windows media player latest version so that it brings all the codec required on your system. Then try your example

Hmm, it seems to be a problem with the machine: I've tried the player on a seperate PC, Windows XP, similar configuration, however with Windows Media Player 10 rather than 11, no problem, runs fine. Both are running DirectX 9.0c (4.09.0000.0904). When I get a chance, I'll try uninstalling Media Player 11, and reinstalling 10, and see what the result is.

you can do one more thing, try running some other file format like mpeg4 or what ever, and see if that runs in the qt demo example if that runs there that should also run in your example.
Or download realtime player that will bring the required codec,

Well, if it plays but display no video, chances are you don't have the codec.

Most probably on windows, you use phonon with directshow backend. Directshow backend is implemented using directshow computer filters.

If you don't know anything about directshow (google the web how it works), try starting graphedit and rendering your file.
Chances are you have the right splitter, the right audio decoder 8if you got sound) but don't have the correct video decoder.

One easy way : install ffdshow which handles almost all formats, see if it's better.
If it's not solved like that, dig a bit deeper inside directshow, especially, try to export the graph generated by phonon backend to root object tree and link externally to see what actually happens.